Biopolymer foams, especially gelled alginate containing foams, have been described for applications such as wound dressings, controlled release delivery systems, cell culture, barrier media for preventing tissue adherence, and bioabsorbable implants. However, these foams are either brittle, difficult to handle, and/or difficult to manufacture, requiring expensive equipment such as freeze dryers.
Two important functions of surgical or wound dressings are the ability to absorb and hold liquid and the ability to wick and transfer exudate of a wound away from the wound site. However, because wound healing is enhanced by keeping the wound bed moist, a wound dressing should absorb and transfer wound exudate away from the wound surface without desiccating the wound bed. Additionally, the wound dressing should release from the wound easily so that removal of the dressing does not damage the newly formed tissue.
Eagles, U.S. Pat. No. 5,840,777, and Bakis, U.S. Pat. No. 5,851,461, for example, each disclose methods of producing gelled polysaccharide foams that can be used as wound dressings. However, there is little or no control over the foam size and the resultant products are relatively difficult to handle. Polyurethane foams have also been used as wound dressings, but these foams do not contain biomaterials and are, consequently, not absorbable when used in implants. Eccard, U.S. Pat. Pub. No. 2003/0180242, discloses solid polymeric foams, but preparation of the foam requires heating and cooling of the reaction mixture to form the foam.
Thus, a need exists for a gelled foam that comprises biomaterials, has a high absorbency, is easy to manufacture and handle, and does not require expensive equipment, such as freeze dryers, for its manufacture.